1. Field of the Invention
The present invention relates to a photosensitive material processing apparatus for processing a photosensitive material by immersing the photosensitive material in a processing solution contained in a processing tank. More particularly, the invention relates to a photosensitive material processing apparatus for processing a photosensitive material in a small amount of processing solution which is contained in a processing tank such that the surface area of the processing solution in the processing tank is small, and to a photosensitive material processing apparatus equipped with a replenisher tank for accommodating a replenisher for replenishing the replenisher into the processing tank.
2. Description of the Related Art
In a photosensitive material processing apparatus for developing a photosensitive material such as photographic film, the photosensitive material is processed by immersing in a processing solution contained in a processing tank. The processing tank is replenished with a replenisher (the processing solution) which is fed from a replenisher tank on the basis of deterioration of the processing solution contained in the processing tank or the lowering of the level of the processing solution in the processing tank.
Since certain processing solutions deteriorate (oxidation) when the processing solutions and air come into contact in order to reduce the deterioration of a processing solution, there have recently been proposed photosensitive material processing apparatuses in which the surface area of the processing solution is small and a photosensitive material is processed in a small amount of a processing solution contained in a processing tank, and photosensitive material processing apparatuses in which floating members are floated on the surface of the processing solution, as described in, for example, Japanese Patent Application Publication (JP-B) No. 53-34734 and Japanese Patent Application Laid-Open (JP-A) Nos. 61-258245, 63-216050, 1-114847, 1-310351, 6-83014, 6-347961, and 7-120900.
According to JP-A No. 63-216050, the cross-sectional area of a processing passage is made small so that a photosensitive material can be washed efficiently by use of a small amount of washing water. However, since the surface area of a processing solution contained in the processing passage becomes small, the height of the processing solution in the processing tank varies greatly with the amount of the processing solution. Variation in the level of the processing solution results in variation in the processing time during which a photosensitive material is immersed in the processing solution, so that a problem that the photosensitive material cannot properly be processed arises.
According to JP-A No. 1-114847, the cross-sectional area of a processing tank is made small, so that a processing solution level varies greatly with variation in the amount of a processing solution contained in the processing tank.
According to JP-A No. 1-310351, a fluid is floated on the surface of a processing solution contained in a processing tank to cover the surface of the processing solution with a fluid layer, and openings are formed in the fluid layer so as to form an inlet and an outlet for feeding a photosensitive material into the processing solution and for taking out therefrom through the openings of the fluid layer. However, no measure is employed against variation in a processing solution level. Also, in this system, when a rack is removed from the processing tank, for example, for maintenance, the fluid adheres to the rack. Thus, when processing is resumed after the rack is replaced, the fluid adhering to the rack transports onto a photosensitive material. No measure is employed against this problem.
According to JP-A No. 6-83014, a processing solution is circulated through a small space defined between the wall of a tank and a rack to process a photosensitive material. Accordingly, the photosensitive material can be processed in a small amount of the processing solution. Mention is made of increasing the surface area of the processing solution in the vicinity of the processing solution where the surface contacts air. However, no measure is employed to isolate the processing solution from the ambient air.
JP-A No. 6-347961 relates to a fluid floated on the surface of a developing replenisher to cover the surface of the developing replenisher with the fluid layer. However, no measure is employed to isolate a developer in a processing tank from the ambient air. No measure is employed against variation of a developer level.
JP-A No. 7-120900 relates to a fluid floated on the surface of a bleach-fix replenisher to cover the surface of the bleach-fix replenisher with the fluid layer. However, no measure is employed to isolate a bleach-fix solution in a processing tank from the ambient air. No measure is employed against variation of the level of the bleach-fix solution.
JP-B No. 53-34734 relates to spherical members floated on the surface of a processing solution to prevent oxidation of the processing solution.
JP-A No. 61-258245 relates to a floating member floated on the surface of a processing solution while being maintained a certain posture of the member.
It is apparent that deterioration of a replenisher in a photosensitive material processing apparatus can be effectively prevented through isolation of the surface of the replenisher from the air. From the viewpoint of the preservation of a replenisher, the methods disclosed in JP-A Nos. 6-347961 and 7-120900 are ideal, in contrast with the former methods wherein a number of solid members are floated on the surface of a processing solution in order to reduce the contact area between the processing solution and the air, since the contact area can be rendered almost zero. However, problems still remain in methods for merely covering the surface of a processing solution with a floating fluid, such that when the amount of a replenisher decreases, the floating fluid together with the replenisher, is drawn into a replenishing pump. As a result, the floating fluid enters a processing tank and consequently adheres to the processing tank, racks, a photosensitive material, and the like. Since removal of the adhered fluid from the processing tank and racks is laborious work, the aforementioned methods of isolating a processing solution from the air were not put into practical use.
Also, a photosensitive material to which the floating fluid adheres undergoes uniformly processing such as development, bleach-fix, washing, and the like. Further, stains were formed on the photosensitive material due to the adhered fluid itself.
In order to avoid such problems, it has been suggested that a solution level sensor be installed in a replenisher tank so that replenishment can be stopped when the solution surface drops to a certain level, to thereby prevent the floating fluid from being drawn into the replenishing pump and to generate a signal to warn an operator to supply replenisher into the replenisher tank. However, even in this method, if the solution level sensor malfunctions, the floating fluid flows into the processing tank. Thus, this method also was not put into practical use.